Publish verified Docker images to GHCR

Make deployments pull immutable CI-built images while keeping test failures diagnosable before any package is published.

build.gradle.kts

@@ -1,4 +1,5 @@
 import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+import org.gradle.api.tasks.testing.logging.TestExceptionFormat
 
 plugins {
     kotlin("jvm") version "2.4.10"
@@ -85,6 +86,10 @@ dependencies {
 
 tasks.test {
     useJUnitPlatform()
+    testLogging {
+        events("failed", "skipped")
+        exceptionFormat = TestExceptionFormat.FULL
+    }
     finalizedBy(tasks.jacocoTestReport)
 }